Improvement in grinding-svjachines



Z Sheets-Sheet 2.

GREG-G. emmme-mc'mm. No.179,854. Patented .Iu1y18,18-75.

' N-PEIERS, FHOTO-UTMOGRAPNER WASHINGTON D. C.

FFIGE.

MAHLON GREGG, OF ROCHESTER, NEW YORK.

IMPROVEMENT IN GRINDING-MACHINES.

Specification forming part of Letters Patent No. 179,854. dated July 18,1876; application filed June 728, 1875.

To all whom it may concern Be it known that I, MAHLON GREGG, of Rochester, in the county of Monroe and State of New York, have invented a new and valuable Improvement in Machine for Grinding Edge-Tools; and 1 do hereby declare that the following is a full, clear, and exact de scription of the construction and operation of the same, reference being had to the annexed drawings, makinga part of this specification, and to the letters and figures of reference marked thereon.

Figure l of the drawing is a representation of a plan view of a machine embodying the improvements in my invention in one position. Fig. 2 is a plan View of the same in another position. Fig. 3 is a vertical sectional view of the machine. Fig. 4 is a partial sectional view of a tool-holder. Figs. 5 and 6 are also tool-holders for different kinds of grinding.

In grinding planer and other knives, it is frequently necessary that the faces of the knives should be slightly concave. These knives have heretofore been ground by hand or otherwise upon the periphery of the grindstone.

Owing to the rocking motion necessary to give the required concavity, askilled mechanic is required to produce the concavity when opcrating by hand, and even then many knives are spoiled during the operation of grinding.

Machines have been constructed to imitate the motion that a skilled mechanic employs when grinding by hand, but these machines are open to several objections, among which are these: The requisite concavity cannot be given the knife, because these machines all grind upon the periphery of the grindstone, and the face of the grindstone becomes glazed and less effective, owing to the fact that too great a surface is presented to the knife.

I have discovered that, by grinding the knife upon the corner of the grindstone at occupies, the required concavity is given to the face of the knife without the use of skilled labor, after the machine has been set to the appropriate angle.

To the accomplishment of these results my invention consists, first, in producing the concavity required in the faces of planer and other knives of that class, by holding the knife upon the corner of the grindstone by means of a tool carriage, having, during the operation of grinding the knife, a longitudinally-reciprocating motion at an angle of forty-five degrees, or thereabout, to the axis of the grindstone; secondly, ofa tool-carriage, provided with a rack, through which longitudinal motion is imparted to it by a pinionwheel upon a lengthwise-sliding shaft, having bearings in a bed-plate, said tool-carriage having its lower surface plain to slide over a plain surface upon the lower front portion of the bed-plate, and its upper portion provided with a tongue, which works in a laterally-adjustable inverted way at the upper part of the bedplate, for thepurposes of permitting longitudinal movement of the tool-carriage in both directions, and lateral pivotal adjustmentof the same to any'angle with the axis of the grindstone.

In the accompanying drawings, A is a grindstone, and B B the frame in which it is supported. D is a bed-plate, the upper face of the forward portion of the base 0 of which is made plain. Lugs E E depend from the base of the bed-plate D, and form the bearings for lengthwise-sliding shaft F, on which is fixed a pinion-Wheel, G, which works through a slot in the base ofthe bed-plate D. A handwheel, H, is used to operate the pinion G. To the upper portion of .the bed-plate D the inverted way I is secured by the slotted arms J J, and screws and washers K K. The inverted way I has recesses L L in its rear face, one near each end, for the reception of the points of the thumbscrews M M. The thumbscrews M M are first passed through the rear vertical portion of the bed-plate D, and then through a face-plate, N, after which nuts or washers O O are screwed upon their points, and the face-plate N secured to the rear face of the inverted way I, by which construction the inverted way I may be moved either forward or backward on the bed-plate D. The

tool-carriage P has the lower face of its base made plain, to correspond with the upper face of the portion 0 of the base-plate D. Lugs Q Q Q, provided with set-screws, project forward from the vertical portion R of the toolcarriage P, at a short distance above the base of the said tool-carriage P. The tool-carriage l is provided with a rack, S, immediately in the rear of the vertical portion R.- The base of the tool-carriage projects slightly below the teeth of the rack S, and the face-plate T, secured to the rear. face of the rack S, also projects in a similar manner. The teeth of the pinion G engage with the teeth of the rack S, and the friction, instead of coming upon the two plain surfaces, is borne by the rack and pinion. A tongue, U, at the upper edge of the vertical portion It of the tool-carriage P, enters the groove V of the inverted way I, and guides the tool-carriage in its longitudinal movement in the bed-plate. The lateral adjustment of the tool-carriageP, and, consequently, the tool-holder and knife when in place, is effected by means of the thumb screws M M, and, owing to the fact that the upper surface of the portion 0 of the base of the bed-plate D and the lower face of the base of the tool-carriage P are plain surfaces, that the rack S is quite wide, and that the shaft F, on which the pinion .G is secured, slides in its bearings, it will be seen that the tool-carriage can be adjusted to any desired angle with relation to the grindstone when the machine is in either of the positions shown in Figs. 1 and 2. Tool-holders for different kinds of tools may be used in the carriage P. Fig. 5 shows a tool-holder for holding a knife that its end may be ground. Fig. 6 shows a holder for grinding the knife to a beveled edge. Fig. 4 shows my improved tool-holder for holding the knife while it is being ground, to produce the required concavity in the face. This knife can also be adjusted to grind the back of the knife without producing the concavity heretofore spoken of.

In Fig. 4, a is the base of the tool-holder, and b is the vertical portion or knife-rest. The vertical portion 1) has a slot, 0, provided with an adjustable stud, (1, consisting of a nut, screw, and washer, which may beadjusted to any point on the slot. At one end of this tool-holder is a projectingstud, e, to which is pivoted a dog, f, the jaw g of which is in front of the face of the knife-rest b. A setscrew, h, in the same end of the tool-holder is used to drive the dog against one end of the knife to hold it against the stud d, to hold the knife in the tool-holder. The rear of the base a is rounded off on its lower edge, and the base has the set-screw i, by which the toolholder is adjusted in the tool-carriage 1?.

Fig. lshows the position the machine should occupy with relation to the grindstone to permit the knife to be ground upon the corner of the stone at an angle of ninety degrees or thereabout to produce-the requisite concavity in the face. The hand-wheel H is used to move the tool carriage P longitudinally in both directions upon the bed-plate D.

Fig.2shows the position the machine should occupy to grind upon the periphery and the corners, of the stone. When in this position the carriage can be adjusted by using the thumb-screws M M to cause the knives to grind upon either corner or upon any portion of the periphery of the stone, and, from the fact that the tool-carriage can be so adjusted, the operator is enabled to keep the periphery of the stone round, as shown in Fig. 2, by properly adjusting the tool-carriage to cause the knives to wear it to a regular curve. When the stone has been worn down by use, the machine should be moved upon the frame to bring it again sufficiently near the stone. A countersunk recess, 76, is made in the face of the base a of the tool-holder, for the reception of the point of the set-screw in the central lug Q. The recess k is made larger than the point of the set-screw, in order that the set-screw '5 may be used to'raise the front of the toolholder by driving the set-screw 6 down. motion of the grindstone is always downward toward the knife, so that the tool-holder needs nothing to hold it against upward pressure- Having thus described my invention of improvements, what I claim as new and useful, and desire to secure by Letters Patent, is

1. In a machine for grinding planer-knives and others of that class, the tool-carriage, having during the operation of grinding the knife alongitudinally-reciprocating motion on a bedplate at an angle of forty-five degrees to the axis of the grindstone, to present the face of the knife in the tool-holder to the corner of the stone throughout its entire length, as and for the purpose set forth.

2. The bed-plate D O, capable of angularadjustment to the axis of the stone, and provided with the rack-gear S, in combination with the tool-carriage 1, having alateral movement, and the inverted way I, adjustable to and from the stone, said carriage being operated by means of the wheel F and pinion, substantially as and for the purpose set forth.

. In testimony that I claim the above I have hereunto subscribed my name in the presence of two witnesses.

MAHLON GREGG.

Witnesses:

NAT. E. ()LIPHANT, \VILLIAM DANIELS.

The 

